1. Field of the Invention
The present invention relates generally to automatic door and gate systems, and more particularly to automatic door safety systems which detect hazardous conditions, obstructions and adjusts operating controls accordingly.
2. Related Art
Systems which control gates and motorized doors have been well-developed in commercial and residential applications. Systems which control doors and gates typically comprise a motorized system which opens and closes the gate or the door upon command such as when a switch is activated or a motion detector senses the arrival of a vehicle in a predetermined area. Such systems often include additional devices and apparatus which assist in the utility or safety of the systems so disposed.
The ubiquitous form of automatic door systems as for home garages or warehouse entry and exit doors or large overhead doors for commercial buildings usually have a transmitter and receiver allowing the doors to be opened remotely when approaching the door. Other systems may have sensors such as proximity sensors, light beams, pressure sensors or the like that automatically close or open doors for safety reasons or for convenience.
Existing systems have had safety means to provide that the gate being operated or the door being closed react should there be a person or other obstruction in the path of the moving gate or door. If a person or a car moves into a moving garage door's path as the door is being closed, the system should sense this condition, thereby allowing the door to stop or reverse itself preventing damage or injury.
Many of the existing systems use some type of device which monitors the visual path across the threshold to be protected such as may be the case with light beams which are used to allow continuous monitoring of a desired path. It would be appreciated that a continuous light beam would be obstructed, even momentarily, by a person walking through the beam or a vehicle blocking the complete path of the light beam. Many photoelectric systems such as described use either visible light or more commonly infrared light to monitor the obstruction path to be protected.
In many instances it is inconvenient or impractical to use wired control or power supply lines between a detector and the photo emitter to supply power or otherwise integrate the system components. Wired systems or electromechanical connections are frequently subject to potential failures from component fatigue induced by physical stress. Safety devices which are put in place to prevent possible injury or damage should always be operating properly to identify such problems and to take the appropriate actions such as to reverse a motor or to stop the action of a control system. If a hazard or obstruction warning or sensing device is not functioning properly, a door or gate may continue to close regardless of whether the obstruction is encountered potentially causing damage or injury and must be avoided with present day safety requirements as they are. Since many systems use hard wired control systems to connect the sensors, part of the system vulnerability is the breaking of wires or the inadvertent disconnection of the control wiring during operation of the equipment or otherwise.
There are also wireless devices now available and deployed which provide for control information to be transmitted or received without direct connection by a hard wired device. Short range wireless systems require batteries. When a battery system is deployed in such a safety device, it is desirable to have as much warning as possible that the battery device being deployed has been depleted so that the system battery can be renewed prior to complete failure of the system. Systems deployed today utilizing batteries could fail if the battery is being depleted to transmit a low battery condition in a wireless control scenario. It would be desirable to deploy wireless obstruction sensing control systems that would be able to provide a long term, low battery condition indication without causing the battery drain from the signaling of the low battery condition to add to the already depleted battery.